Evlune

How to Fix Node.js Memory Leaks Caused by Unclosed EventEmitters in Production This article explains how to identify and resolve a common but often overlooked source of memory leaks in Node.js production applications: unclosed EventEmitters. We'll cover practical debugging techniques, prevention strategies, and how to ensure your listeners are properly cleaned up to prevent your application's memory usage from climbing uncontrollably. So you've deployed your Node.js application. It's running smoothly. But then, over days or weeks, you notice something strange. Memory usage is creeping up. It doesn't go down. Honestly, it just climbs and climbs until the process eventually crashes or gets killed by the OS. You restart it, and the cycle begins again. This is the classic signature of a memory leak. And one of the sneakiest culprits, especially in long-running servers, is the unclosed EventEmitter. It's a subtle bug that can be devastating in production. Why...

How to Fix N+1 Query Performance Degradation in Hibernate This article explains the N+1 query problem in Hibernate, a common performance killer in Java applications. We'll break down what causes it, how to identify it, and the practical strategies you can use to eliminate it. You'll learn about eager fetching, JOIN FETCH, entity graphs, and batch fetching to optimize your database interactions and prevent your app from slowing to a crawl. So you've built your Hibernate-powered application. It works. Data goes in, data comes out. But then, as you add more features and more data, things start to feel... sluggish. Pages that loaded quickly now take several seconds. Your database server's CPU graph starts looking like a mountain range. Honestly, you might be dealing with one of the most classic Hibernate performance issues: the N+1 query problem. It's a sneaky one. Your code looks clean, but under the hood, it's generating a flood of unnecessary database calls. L...

How to Handle Goroutine Leaks in Go HTTP Servers Using Context Cancellation This article explains a common and serious problem in Go server development: goroutine leaks. We'll focus specifically on HTTP servers and how unfinished goroutines can silently consume memory. The core solution is proper context cancellation. You'll learn practical patterns to propagate cancellation signals, clean up resources, and stop those leaks for good. It's about writing robust, production-ready servers. Honestly, if you've written a Go HTTP server that does anything beyond returning "Hello World," you've probably launched a goroutine. Maybe to fetch data from a database. Or to call an external API. And that's fine. Goroutines are amazing. They're lightweight. They're the reason Go is so good at concurrency. But here's the thing. They can also be sneaky. If you don't manage their lifecycle, they stick around. They leak. And a leaking goroutine is like ...

How to Solve Java GC Pause Spikes in High-Throughput Spring Boot Microservices This article is a practical guide for developers facing performance degradation due to Garbage Collection (GC) pauses in demanding Spring Boot applications. We'll move from diagnosing the root causes to implementing concrete solutions, covering JVM tuning, architectural adjustments, and monitoring strategies. You'll learn how to smooth out those disruptive spikes and achieve more predictable latency. Honestly, if you're running a high-throughput Spring Boot service, you've probably seen it. Everything is humming along, graphs look good, and then—bam. Latency spikes through the roof for a few hundred milliseconds. The dashboard lights up red. You check the logs, and there it is: a full GC cycle. These pauses are more than an annoyance; they can violate SLAs, cause upstream timeouts, and create a terrible user experience. So let's talk about why this happens and, more importantly, what y...

How to Handle Rust Borrow Checker Lifetime Errors in Recursive Async Functions This article tackles a notoriously tricky Rust problem: the intersection of recursion, async/await, and the borrow checker's lifetime rules. We'll break down why these errors happen, explore concrete strategies to fix them, and look at practical examples. You'll learn how to restructure your code, choose the right data types, and work with the compiler instead of fighting it. Honestly, if you've written Rust for any length of time, you've probably met the borrow checker. It's that strict friend who keeps you from making memory safety mistakes. But combine its rules with a function that calls itself and uses async/await? That's when things can get, well, interesting. The compiler messages start to look like abstract art, and the usual fixes don't seem to apply. So let's untangle this knot together. Why This Combination Is So Problematic To understand the fix, you ne...

How to Fix PostgreSQL Deadlock Detected Errors in Concurrent Update Transactions This article explains the technical causes behind PostgreSQL's "deadlock detected" errors, a common issue in applications with high concurrency. We'll break down the classic transaction cycle that creates a deadlock. You'll learn practical strategies to prevent them, from query ordering to transaction isolation. And we'll cover how to resolve deadlocks when they do occur, ensuring your database stays responsive under load. Honestly, if you're building anything that handles simultaneous users or background jobs, you've probably seen this error. It's that frustrating "deadlock detected" message that rolls back your carefully crafted transaction. It feels random, but it isn't. It's a predictable outcome of how PostgreSQL manages locks to keep your data consistent. When two or more transactions get stuck, each waiting for a resource the other holds, th...